update custom error boundary section; add ToC

Author: inventarSarah

docs/platforms/javascript/guides/react/features/react-router/v6.mdx

@@ -4,7 +4,11 @@ description: "Learn how to instrument your React Router v6 application with Sent
 sidebar_order: 20
 ---
 
-Apply the following setup steps based on your routing method and create a [custom error boundary](#custom-error-boundaries) to make sure Sentry automatically captures rendering errors.
+Apply the following setup steps based on your routing method and create a [custom error boundary](#usage-with-custom-error-boundaries) to make sure Sentry automatically captures rendering errors:
+
+<TableOfContents
+  ignoreIds={["usage-with-custom-error-boundaries", "next-steps"]}
+/>
 
 ## Usage with `createBrowserRouter` or `createMemoryRouter`
 
@@ -148,9 +152,11 @@ ReactDOM.render(
 
 Now, Sentry should generate `pageload`/`navigation` transactions with parameterized transaction names (for example, `/teams/:teamid/user/:userid`), where applicable. This is only needed at the top level of your app, unlike React Router v4/v5, which required wrapping every `<Route />` you wanted parametrized.
 
-## Custom Error Boundaries
+## Usage With Custom Error Boundaries
 
-When using `react-router`, errors thrown inside route elements will only be re-thrown in **development mode** while using [`strict mode`](https://react.dev/reference/react/StrictMode). In production, these errors won't be surfaced unless manually captured. If you **don't** have a custom error boundary in place, `react-router` will create a default one that "swallows" all errors.
+When using `react-router`, errors thrown inside route elements will only be re-thrown in **development mode** while using [`strict mode`](https://react.dev/reference/react/StrictMode).\
+In production, these errors won't surface unless captured manually. If you **don't** have a custom error boundary in place, `react-router` will create a default one that "swallows" all errors.\
+Hence, to capture these errors with Sentry in production, we strongly recommend to implement a custom error boundary.
 
 <Alert>
   This only applies to render method and lifecycle errors since React doesn't

docs/platforms/javascript/guides/react/features/react-router/v7.mdx

@@ -9,8 +9,12 @@ sidebar_order: 10
   the docs [here](/platforms/javascript/guides/react-router/).
 </Alert>
 Apply the following setup steps based on your routing method and create a
-[custom error boundary](#custom-error-boundaries) to make sure Sentry
-automatically captures rendering errors.
+[custom error boundary](#usage-with-custom-error-boundaries) to make sure Sentry
+automatically captures rendering errors:
+
+<TableOfContents
+  ignoreIds={["usage-with-custom-error-boundaries", "next-steps"]}
+/>
 
 ## Usage with `createBrowserRouter` or `createMemoryRouter`
 
@@ -152,9 +156,11 @@ ReactDOM.render(
 
 Now, Sentry should generate `pageload`/`navigation` transactions with parameterized transaction names (for example, `/teams/:teamid/user/:userid`), where applicable. This is only needed at the top level of your app, unlike React Router v4/v5, which required wrapping every `<Route />` you wanted parametrized.
 
-## Custom Error Boundaries
+## Usage With Custom Error Boundaries
 
-When using `react-router`, errors thrown inside route elements will only be re-thrown in **development mode** while using [`strict mode`](https://react.dev/reference/react/StrictMode). In production, these errors won't be surfaced unless manually captured. If you **don't** have a custom error boundary in place, `react-router` will create a default one that "swallows" all errors.
+When using `react-router`, errors thrown inside route elements will only be re-thrown in **development mode** while using [`strict mode`](https://react.dev/reference/react/StrictMode).\
+In production, these errors won't surface unless captured manually. If you **don't** have a custom error boundary in place, `react-router` will create a default one that "swallows" all errors.\
+Hence, to capture these errors with Sentry in production, we strongly recommend to implement a custom error boundary.
 
 <Alert>
   Note, that this only applies to render method and lifecycle errors since React